The Consumer Price Index, or CPI, is the Bureau of Labor Statistics measure of how prices change over time. The agency posts a monthly news release that summarizes the latest results. At the time of writing, the summary page the BLS maintains at its Consumer Price Index Summary carried the title "2026 M09 Results."
Many readers assume a published number never changes. Others assume every government figure gets revised. This piece does not settle that question for CPI. It explains what we can and cannot say from the BLS pages we reviewed, and how to check the rest yourself.
What the monthly CPI release is
The BLS publishes the CPI summary as a news release tied to a reference month. That is the number markets, reporters and policymakers see first. The page title itself names the month it covers, which is a useful habit to copy. When you quote a figure, you should know which release it came from.
The BLS also keeps a general overview of the index on its CPI presentation page. An older copy is preserved in a September 2023 archive. Archived pages like this show that the agency documents how the index is described over time.
What the sources do not say about revisions
The pages we retrieved did not state whether CPI figures are revised after first release. They did not say how often a revision might happen, or by how much. The text we could extract from several of them was mostly page titles and site navigation, so the methods behind any revision were not visible to us.
That gap matters. We could repeat common claims, such as that seasonally adjusted figures get recalculated on a schedule while unadjusted figures are rarely touched. But we could not tie those claims to the pages we reviewed, so we are not presenting them as fact. If you need to know which series can change, the answer has to come from the BLS documentation itself.
We also could not confirm how soon after a month ends the release appears. The release calendar is the place to check that, not a rule of thumb from an article.
Payroll revisions are a different story
One source in our set does discuss revisions, but it covers jobs data. A commentary from the Upjohn Institute addresses BLS revisions to payroll figures. It does not address CPI.
So it would be a mistake to carry its conclusions over. Payroll numbers and price numbers come from different surveys. Whatever is true for one tells us nothing certain about the other. Treat any claim that blends the two with suspicion.
Where to check a specific series
The BLS runs several pages that are likely to answer the revision question directly. We could not read their substantive contents, so we point to them rather than summarize them.
- The CPI Notices page, where the agency posts announcements about the index.
- The CPI News Release Technical Note, which should describe methods behind the monthly release.
- The CPI Frequently Asked Questions page, which covers common questions about the index.
Start with the FAQ and the technical note. If either addresses revisions, it will name the series involved, such as an all-items index or a seasonally adjusted one. Then look at the notices page for any announced changes.
How to cite a CPI figure without guessing
You do not need to know the revision policy to cite a number carefully. Write down what you used. Name the series, say whether it was seasonally adjusted, and note the release title and the date you pulled it.
That one detail helps most when two people compare notes. If your figure differs from a colleague's by a small amount, a different release date is a likely first suspect. A recorded source lets you check in minutes instead of arguing for an afternoon.
If a figure feeds something with real money attached, such as a lease or a pay adjustment, read the agreement's own wording on which index it names. We have no sourced guidance on how contracts treat revised data, so ask the party who wrote it or a qualified professional.
The honest summary is short. The monthly CPI release exists, and the BLS documents the index in several places. Whether a given number changes afterward is something the agency's own pages must answer. Go to them before you repeat a claim either way.
